Sound insulation materials are used in a variety of settings where it is desired to dampen noise from an external source. For example, sound insulation materials have been used in applications such as in appliances to reduce the sound emitted into the surrounding areas of a home, in automobiles to reduce mechanical sounds of the motor and road noise, and in office buildings to attenuate sound generated from the workplace, such as from telephone conversations or from the operation of office equipment. In automobiles, the insulation material also relies upon thermal shielding properties to reduce or prevent the transmission of heat from various heat sources in the automobile (e.g., engine, transmission, exhaust, etc.) to the passenger compartment of the vehicle. Acoustical insulation typically relies upon both sound absorption (i.e., the ability to absorb incident sound waves) and transmission loss (i.e., the ability to reflect incident sound waves) to provide adequate sound attenuation.
Conventional acoustical insulation materials include materials such as foams, compressed fibers, fiberglass batts, felts, and nonwoven webs of fibers such as meltblown fibers. Although there are numerous acoustical insulation products in existence in the art, there is still a need for insulation products that have sufficient structural properties so that the insulation products can be employed in end-use applications that require high strength, high modulus insulation materials.
There is also a need for acoustical insulation materials that exhibit superior sound attenuating properties, improved structural and thermal properties, and that are lightweight and low in cost.
The invention will be more readily understood from the following descriptions thereof given, by way of example, with reference to the accompanying drawings.